Bug 2173436 (CVE-2023-1077)

Summary:	CVE-2023-1077 kernel: Type confusion in pick_next_rt_entity()
Product:	[Other] Security Response	Reporter:	Alex <allarkin>
Component:	vulnerability	Assignee:	Nobody <nobody>
Status:	NEW ---	QA Contact:
Severity:	medium	Docs Contact:
Priority:	medium
Version:	unspecified	CC:	acaringi, arachman, bhu, chwhite, crwood, ddepaula, debarbos, dfreiber, dvlasenk, ezulian, fhrbata, hkrzesin, jarod, jburrell, jfaracco, jferlan, jforbes, jlelli, joe.lawrence, jshortt, jstancek, jwyatt, kcarcia, kernel-mgr, lgoncalv, lveyde, lzampier, michal.skrivanek, mperina, nmurray, ptalbert, qzhao, rogbas, rvrbovsk, scweaver, tyberry, vkumar, walters, williams
Target Milestone:	---	Keywords:	Security
Target Release:	---
Hardware:	All
OS:	Linux
Whiteboard:
Fixed In Version:	kernel 6.1.16	Doc Type:	If docs needed, set a value
Doc Text:	A memory corruption flaw was found in the Linux kernel's scheduler subsystem. This could allow a local user to crash the system or potentially escalate their privileges on the system.	Story Points:	---
Clone Of:		Environment:
Last Closed:		Type:	---
Regression:	---	Mount Type:	---
Documentation:	---	CRM:
Verified Versions:		Category:	---
oVirt Team:	---	RHEL 7.3 requirements from Atomic Host:
Cloudforms Team:	---	Target Upstream Version:
Embargoed:
Bug Depends On:	2212185, 2212186, 2212187, 2212188, 2212189
Bug Blocks:	2172923

Description Alex 2023-02-26 17:28:50 UTC

pick_next_rt_entity() may return a type confused entry, not
detected by the BUG_ON condition, as the confused entry will not be
NULL, but list_head.
The buggy error condition would lead to a type confused entry with the
list head, which would then be used as a type confused
sched_rt_entity, causing memory corruption.

It is hard to trigger it, because found it with static analysis and were not able to trigger it manually. But pick_next_rt_entity() may return a type confused entry, the BUG_ON will never trigger since it assumes the error condition is NULL, while the buggy error condition would be a type confused entry with the list head, which would then be used as a type confused sched_rt_entity.

Reference:
https://git.kernel.org/pub/scm/linux/kernel/git/next/linux-next.git/commit/?id=7c4a5b89a0b5a57a64b601775b296abf77a9fe97

Comment 3 Alex 2023-06-04 14:48:39 UTC

Created kernel tracking bugs for this issue:

Affects: fedora-all [bug 2212185]

Comment 5 Justin M. Forbes 2023-06-05 12:36:53 UTC

This was fixed for Fedora in the 6.1.16 stable kernel update.